ML17223A630

Annual Environ Operating Rept, Vol 1 1989

ML17223A630
Person / Time
Site:	Saint Lucie
Issue date:	12/31/1989
From:	APPLIED BIOLOGY, INC.
To:
Shared Package
ML17223A629	List: ML17223A628 ML17223A630
References
AB-603, AB-603-V01, AB-603-V1, NUDOCS 9005010191
Download: ML17223A630 (174)

Text

APPLIED BIOLOGY, INC. AB-603 FLORIDA POWER & LIGHT COMPANY ST. LUCIE UNIT 2 ANNUAL ENVIRONMENTALOPERATING REPORT VOLUME I 1989 2968 A NORTH DECATUR ROAD ~ ATLANTA, GEORGIA 30033 ~ 404-296-3900

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AB-603 FLORIDA POWER & LIGHT COMPANY ST. LUClE UNlT 2 ANNUALENVIRONMENTAL OPERATING REPORT 198S VOLUME 1 APRIL 1990 FLORIDA POWER 5 LIGHT COMPANY JUNO BEACH, FLORIDA APPLIED BIOLOGY, INC.

ATLANTA,GEORGIA

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ENVIRONMENTALOPERATING REPORT TABLE OF CONTENTS TABLE OF CONVERSION FACTORS FOR METRIC UNITS ii EXECUTIVE

SUMMARY

. Iil Introduction.

Turtle Nesting Survey Intake Canal Monitoring Other Related Activities . iv INTRODUCTION ..

Background .

Area Description.

Plant Description TURTLES Introduction ..

Materials and Methods. .10 Nesting Survey. 10 Intake Canal Monitoring .

Studies to Evaluate and/or Mitigate Intake Entrapment ....,. 14 Results and Discussion. 14 Nesting Survey. 14 Distribution of Loggerhead Nests Along Hutchinson Island. 14 Estimates of Total Loggerhead Nesting on Hutchinson Island .19 Temporal Loggerhead Nesting Patterns 20 Predation on Loggerhead Turtle Nests. 21 Green and Leatherback Turtle Nesting . 22 Intake Canal Monitoring . 24 Relative Abundance and Temporal Distribution 24 Size-Class Distributions 27 Sex Ratios 29 Capture Efficiencies. 31 Relative Condition 32 Mortalities. 34 Recapture Incidents 36 Summary 37 LITERATURE CITED . .41 FIGURES .49 TABLES 70

I TABLE OF CONVERSION FACTORS FOR METRIC UNITS To convert Multi I b To obtain centigrade (degrees) ( C x 1.8) + 32 fahrenheit (degrees) centigrade (degrees) C + 273.18 kelvin (degrees) centimeters (cm) 3.937 x 10 inches centimeters (cm) 3.281 x 10 feet centimeters/second (cm/sec) 3.281 x 10 feet per second cubic centimeters (cd) 1.0 x 10 liters grams (g) 2.205 x 10 pounds grams (g) 3.527 x 10 ounces (avoirdupois) hectares (ha) 2 471 'acres kilograms (kg) 1.0x 10 grams kilograms (kg) 2.2046 pounds kitograms (kg) 3.5274 x 10 ounces (avoirdupois) kilometers (km) 6.214 x 10 miles (statute) kilometers (km) 1.0 x 10 millimeters liters (I) 1.0 x 10 cubic centimeters (cd) liters (I) 2.642 x 10 gallons (US liquid) meters (m) 3.281 feet meters (m) 3.937 x 10 inches meters (m) 1.094 yards milligrams (mg) 1.0 x10 grams milligrams/liters (mg/I) 1.0 parts per million milliliters (ml) 1.0 x 10 liters (US liquid) millimeters (mm) 3.937 x 10 inches millimeters (mm) 3.281 x 10 feet square centimeters (cm ) 1.550 x 10 square inches square meters (m ) 1.076 x 10 square feet square millimeters (mm ) 1.55 x 10 square inches

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EXECUTIVE

SUMMARY

INTRODUCTION The St. Lucie Plant is an electric generating station on Hutchinson Island in St. Lucie County, Florida. The plant consists of two nuclear-fueled 850-MW units; Unit 1 was placed on-line in March 1976 and Unit 2 in May1983. This document has been prepared to satisfy the requirements contained in the United States Nuclear Regulatory Commission's Appendix B Environmental Protection Plan (EPP) to St. Lucie Unit 2 Facility Operating License No. NPF-16. This report discusses environmental protection activities related to sea turtles as required by Subsection 4.2 of the EPP. Other routine annual reporting requirements are addressed in Volume 2, also entitled "St. Lucie Unit No. 2 Annual Environmental Operating Report."

TURTLE NESTING SURVEY There have been considerable year-to-year fluctuations in sea turtle nesting activity on Hutchinson Island since monitoring began in 1971. Low nesting activity in 1975 and 1981 - 1983 in the vicinity of the power plant was attributed to construction of plant in-take and discharge structures. Nesting returned to normal or above normal levels fol-lowing both periods of construction. Power plant operation exclusive of construction has had no significant effect on nesting near the plant. Data collected through 1989 have shown no long-term reductions in total nesting, total emergences or nesting suc-cess on the island. Formal requirements to conduct this program expired in 1986 but were voluntarily continued in 1989 with agreement from federal and state agencies.

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INTAKE CANAL MONITORING Since plant operation began in 1976, 2,061 sea turtles (including 90 recaptures) rep-resenting five different species have been removed from the intake canal. Eighty-four percent of these were loggerheads. Differences in the numbers of turtles found during different months and years were attributed to natural variation in the occurrences of turtles in the vicinity of the plant, rather than to any influence of the plant itself. The majority of turtles removed from the intake canal (about 93 percent) were captured alive, tagged and released back into the ocean. Turtles confined between the A1A bar-rier net and intake headwalls usually resided in the canal for a relatively short period of time, and most were in good to excellent condition when caught.

OTHER RELATED ACTIVITIES Studies to evaluate various cooling water intake sea turtle deterrent systems, as re-quired by the NRC's Unit 2 Environmental Protection Plan, were conducted during 1982 and 1983. Results and evaluations of those studies were presented to regulatory agen-cies during 1984, and the requirement is now considered completed.

I INTRODUCTION BACKGROUND This document has been prepared to satisfy the requirements contained in the United States Nuclear Regulatory Commission's (NRC) Appendix B Environmental Protection Plan to St. Lucie Unit 2 Facility Operating License No. NPF-16.

In 1970, Florida Power & Light Company (FPL) was issued Permit No. CPPR-74 by the United States Atomic Energy Commission, now the Nuclear Regulatory Commis-sion, that allowed construction of Unit 1 of the St. Lucie Plant, an 850-MW nuclear-powered electric generating station on Hutchinson Island in St. Lucie County, Florida.

St Lucie Plant Unit 1 was placed on-line in March 1976. In May 1977, FPL was issued Permit No. CPPR-144 by the NRC for the construction of a second 850-MW nuclear-powered unit, Unit 2 was placed on-line in May 1983 and began commercial operation in August of that year.

St, Lucie Plant Units 1 and 2 use the Atlantic Ocean as a source of water for once-through condenser cooling. Since 1971, the potential environmental effects resulting from the intake and discharge of this water have been the subject of FPL-sponsored biotic studies at the site.

Baseline environmental studies of the marine environment adjacent to the St. Lucie Plant were described in a series of reports published by the Florida Department of Natural Resources (Camp et al., 1977; Futch and Dwinell, 1977; Gallagher, 1977; Gal-lagher and Hollinger, 1977; Worth and Hollinger, 1977; Moffler and Van Breedveld,

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1979; Tester and Steidinger, 1979; Walker, 1979; Walker et al., 1979; Walker and Steidinger, 1979). The results of Unit 1 operational and Unit 2 preoperational biotic monitoring at the St. Lucie Plant were presented in six annual reports (ABI, 1977, 1978, 1979, 1980a, 1981b, 1982). In January 1982, a National Pollutant Discharge Elimina-tion System (NPDES) permit was issued to FPL by the US Environmental Protection Agency (EPA). The EPA guidelines for the St. Lucie site biological studies were based on the document entitled "Proposed St. Lucie Plant Preoperational and Operational Biological Monitoring Program- August1981" (ABI, 1981c). Findings from these studies were reported in three annual reports (ABI, 1983, 1984a, 1985a). The EPA biotic monitoring requirements were deleted from the NPDES permit in 1985.

Jurisdiction for sea turtle studies is with the NRC, which is considered to be the lead federal agency relative to consultation under the Endangered Species Act. Previous results dealing exclusively with sea turtle studies are contained in six environmental operating reports (ABI, 1984b, 1985b, 1986, 1987, 1988, 1989). This report describes the 1989 environmental protection activities related to sea turtles, as required by Sub-section 4.2 of the St. Lucie Plant Unit 2 Environmental Protection Plan.

AREA DESCRIPTION The St. Lucie Plant is located on a 457-ha site on Hutchinson Island on Florida's east coast (Figures 1 and 2). The plant is approximately midway between the Ft. Pierce and St. Lucie Inlets. It is bounded on its east side by the Atlantic Ocean and on its west side by the Indian River Lagoon.

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Hutchinson Island is a barrier island that extends 36 km between inlets and obtains its maximum width of 2 km at the plant site. Elevations approach 5 m atop dunes bor-dering the beach and decrease to sea level in the mangrove swamps that are common on much of the western side. Island vegetation is typical of southeastern Florida coas-tal areas; dense stands of Australian pine, palmetto, sea grape and Spanish bayonet present at the higher etevations, and mangroves abound at the lower elevations.

I're Large stands of black mangroves, including some on the plant site, have been killed by flooding for mosquito control over past decades.

The Atlantic shoreline of Hutchinson Island is composed of sand and shell hash with intermittent rocky promontories protruding through the beach face along the southern end of the island. Submerged coquinoid rock formations parallel much of the island off the ocean beaches. The ocean bottom immediately offshore from the plant site con-sists primarily of sand and shell sediments. The unstable substrate limits the estab-lishment of rooted macrophytes.

The Florida Current, which flows parallel to the continental shelf margin, begins to diverge from the coastline at West Palm Beach. At Hutchinson Island, the current is approximately 33 km offshore. Oceanic water associated with the western boundary of the current periodically meanders over the inner shelf, especially during summer months.

PLANT DESCRIPTION The St. Lucie Plant consists of two 850-MW nuclear-fueled electric generating units that use nearshore ocean waters for the plant's once-through condenser cooling water

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system. Water for the plant enters through three submerged intake structures located about 365 m offshore (Figure 2). Each of the intake structures is equipped with a velocity cap to minimize fish entrainment. Horizontal intake velocities are less than 30 cm/sec.

From the intake structures, the water passes through submerged pipes (two 3.7 m and one 4.9 m in diameter) under the beach and dunes that lead to a 1,500-m long intake canal This canal transports the water to the plant. After passing through the plant, the

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heated water is discharged into a 670-m long canal that leads to two buried discharge pipelines. These pass underneath the dunes and beach and along the ocean floor to the submerged discharges, the first of which is approximately 365 m offshore and 730 m north of the intake.

Heated water leaves the first discharge line from a Y-shaped nozzle (diffuser) at a design velocity of 396 cm/sec. This high-momentum jet entrains ambient water, result-ing in rapid heat dissipation. The ocean depth in the area of the first discharge is about 6 m. Heated water leaves the second discharge line through a series of 48 equally spaced high velocity jets along a 323-m manifold (multiport diffuser) This diffuser starts

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168 m beyond the first discharge and terminates 856 m from shore. The ocean depth at discharge along this diffuser is from about 10 to 12 m. As with the first diffuser, the purpose of the second diffuser is to entrain ambient water and rapidly dissipate heat.

From the points of discharge at both diffusers, the warmer water rises to the surface and forms a surface plume of heated water. The plume then spreads out on the sur-face of the ocean under the influence of wind and currents and the heat dissipates to the atmosphere.

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TURTLES The NRC's St. Lucie Unit 2 Appendix B Environmental Protection Plan issued April 1983 contains the following technical specifications:

4.2 Terrestrial A vatic Is ue Issues on endangered or threatened sea turtles raised in the Unit 2 FES-OL [NRC, 1982] and in the Endangered Species Biological As-sessment (March 1982) [Bellmund et al., 1982] will be addressed by programs as follows:

Beach nesting surveys for all species of sea turtles will be conducted on a yearly basis for the period of 1982 through 1986. These sur-veys will be conducted during the nesting season from ap-proximately mid-April through August.

The Hutchinson Island beach will be divided into 36 one-km-long survey areas. In addition, the nine 1.25-km-long survey areas used in previous studies (1971-1979) will be maintained for comparison purposes. Survey areas will be marked with numbered wooden pla-ques and/or existing landmarks.

The entire beach will be surveyed seven days a week. All new nests and false crawls will be counted and recorded in each area. After counting, all crawl tracks will be obliterated to avoid recounting.

Predation on nests by raccoons or other predators will be recorded as it occurs. Records will be kept of any seasonal changes in beach topography that may affect the suitability of the beach for nesting.

4.2.2 A program that employs light and/or sound to deter turtles from the intake structure will be conducted. The study will determine with laboratory and field experiments if sound and/or light will result in a reduction of total turtle entrapment rate.

The study shall be implemented no later than after the final removal from the ocean of equipment and structures associated with con-struction of the third intake structure and the experiments shall ter-minate 18 months later. Four months after the conclusion of the experimental period, a report on the results of the study will be sub-mitted to NRC, EPA, National Marine Fisheries Service (NMFS), and the US Fish and Wildlife Service (USFWS) for their evaluation. If a statistically significant reduction in annual total turtle entrapment rate of 80 percent or greater can be demonstrated, using the developed technology and upon FPL receiving written concurrence by NRC, EPA, NMFS, and USFWS then permanent installation of the deterrent system shall be completed and functioning no later than 18 months after the agencies'oncurrence. The design of this study needs to take into account the significant annual variation in turtle entrapment observed in the past.

If an 80 percent reduction of turtle entrapment cannot be projected to all three intake structures, then an interagency task force com-posed of NRC, EPA, NMFS, USFWS, and FPL shall convene 18 months after completion of the third intake and determine if other courses of action to mitigate and/or reduce turtle entrapment are warranted (such as physical barrier, emergence of new technology or methods to deter turtles).

4.2.3 Alternative methods or procedures for the capture of sea turtles entrapped in the intake canal will be evaluated. If a method or pro-cedure is considered feasible and cost effective and may reduce capture mortality rates, it will be field tested in the intake canal.

4.2.5 Ca ture and Release Pro ram Sea turtle removal from the intake canal will be conducted on a con-tinuing basis. The turtles will be captured with large mesh nets, or other suitable nondestructive device(s), if deemed appropriate. A formalized daily inspection, from the shoreline, of the captul'e device(s) will be made by a qualified individual when the device(s) are deployed. The turtles will be identified to species, measured, weighed (if appropriate), tagged and released back into the ocean.

Records of wounds, fresh or old, and a subjective judgement on the condition of the turtle (e.g., barnacle coverage, underweight) will be maintained. Methods of obtaining additional biological/physiologi-cal data, such as blood analyses and parasite loads, from captured

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sea turtles will be pursued. Dead sea turtles will be subjected to a gross necropsy, if found in fresh condition.

INTRODUCTION Hutchinson Island, Florida, is an important rookery for the loggerhead turtle, Caret-ta oaretta and also supports some nesting of the green turtle, ~Chel nia ~mdas and IR I Ik 9 kt I,~dk I I td td II t 1.,1999;9 .1999:9 I-Iagher et al., 1972; Worth and Smith, 1976; Williams-Walls et al., 1983). Allthree species are protected by state and federal statutes. The federal government classified the log-gerhead turtle as a threatened species. The leatherback turtle and the Florida nesting population of the green turtle are listed by the federal government as endangered species. Because of reductions in world populations of marine turtles resulting from coastal development and fishing pressure (NMFS, 1978), maintaining the vitality of the Hutchinson Island rookery is important.

It has been a prime concern of FPL that the construction and subsequent opera-9 tion of the St. Lucie Plant would not adversely affect the Hutchinson Island rookery.

Because of this concern, FPL has sponsored monitoring of marine turtle nesting ac-tivity on the island since 1971.

Daytime surveys to quantify nesting, as well as nighttime turtle tagging programs, were conducted in odd numbered years from 1971 through 1979. During daytime nest-ing surveys, nine 1.25-km-long survey areas were monitored five days per week (Figure 3). The St. Lucie Plant began operation in 1976; therefore, the first three survey years (1971, 1973 and 1975) were preoperational. Though the power plant was not operat-ing during 1975, St. Lucie Plant Unit No. 1 ocean intake and discharge structures were

installed during that year. Installation of these structures included construction activities conducted offshore from and perpendicular to the beach. Construction had been com-pleted and the plant was in full operation during the 1977 and 1979 surveys.

A modified daytime nesting survey was conducted in 1980 during the preliminary construction of the ocean discharge structure for St. Lucie Plant Unit 2. During this study, four of the previously established 1.25-km-long survey areas were monitored.

Additionally, eggs from turtle nests potentially endangered by construction activities were relocated.

Every year from 1981 through 1989, thirty-six 1-km-long survey areas comprising the entire island were monitored seven days a week during the nesting season (Figure 3). The St. Lucie Plant Unit 2 discharge structure was installed during the 1981 nest-ing season. Offshore and beach construction of the Unit 2 intake structure proceeded throughout the 1982 nesting season and was completed near the end of the 1983 season. Construction activities associated with installation of both structures were similar to those conducted when Unit 1 intake and discharge structures were installed.

Eggs from turtle nests potentially endangered by construction activities were relocated during all three years.

Requirement 4.2.1 of the NRC's St. Lucie Unit 2 Appendix B Environmental Protec-tion Plan was completed with submission of the 1986 nesting survey data (ABI, 1987).

The nesting survey was continued voluntarily through 1989 with agreement from federal and state agencies. Results are presented in this report and discussed in relation to previous findings.

l In addition to monitoring sea turtle nesting activities and relocating nests away from plant construction areas, removal of turtles from the intake canal has been an integral part of the St. Lucie Plant environmental monitoring program. Turtles entering the ocean intake structures are entrained with cooling water and rapidly transported through the intake pipes into an enclosed canal system where they must be manually captured and-returned to the ocean. Since the plant became operational in 1976, turtles entrapped in the intake canal have been systematically captured, measured, weighed, tagged and released.

Previous publications and technical reports have presented findings of the nesting surveys, nest relocation activities and canal capture program (Gallagher et al., 1972; Worth and Smith, 1976; ABI, 1978, 1980a, 1981a, 1982, 1983, 1984b, 1985b, 1986, 1987, 1988, 1989; Williams-Walls et al., 1983; Proffitt et al., 1986; Ernest et al., 1988, 1989; Martin et al., 1989a, 1989b; O'ara and Wilcox, in press). Results of studies to assess the effects of thermal discharges on hatchling swimming speed have also been reported (ABI, 1978; O'ara, 1980). The purpose of this report is to 1) present 1989 sea turtle nesting survey data and summarize observed spatial and temporal nesting patterns since 1971, 2) document and summarize predation on turtle nests since 1971, and 3) present 1989 canal capture data and summarize comparable data collected since 1976.

MATERIALSAND METHODS Nestin Sur ve Methodologies used during previous turtle nesting surveys on Hutchinson Island were described by Gallagher et al. (1972), Worth and Smith (1976) and ABI (1978, 1981 a, 1982, 1987, 1988, 1989). Methods used during the 1989 survey were designed to allow comparisons with these previous studies.

On 10 and 13 April 1989, preliminary nest surveys were conducted along Hutchin-son Island from the Ft. Pierce Inlet south to the St. Lucie Inlet. From 17 April through 8 September, nest surveys were conducted on a daily basis. After 8 September, several additional surveys were conducted to confirm that nesting had ceased, the last survey being conducted on 15 September. Biqlogists used small off-road motorcycles to sur-vey the island each morning. New nests, non-nesting emergences (false crawls), and nests destroyed by predators were recorded for each of the thirty-six 1-km-long sur-vey areas comprising the entire island (Figure 3) The nine 1.25-km-long survey areas

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established by Gallagher et al. (1972) also'were monitored so comparisons could be made with previous studies.

During the daily nest monitoring, any major changes in topography that may have affected the beach's suitability for nesting were recorded. In addition, each of the thir-ty-six1-km-long survey areas has been systematically analyzed and categorized based on beach slope (steep, moderate, etc.), width from high tide line to the dune, presence of benches (areas of abrupt vertical relief) and miscellaneous characteristics (packed 10

I sand, scattered rock, vegetation on the beach, exposed roots on the primary dune, etc.).

In a cooperative effort, data from stranded turtles found during beach surveys were routinely provided to the National Marine Fisheries Service through the Sea Turtle Stranding and Salvage Network.

Intake Canal Monitorin Most turtles entrapped in the St. Lucie Plant intake canal were removed by means of large-mesh tangle nets fished between the intake headwalls and a barrier net located at the Highway A1A bridge (Figure 2). Nets used during 1989 were from 30 to 40 m in length, 3 to 4 m deep and composed of 40 cm stretch mesh nylon twine. Large floats were attached to the surface, and unweighted lines used aiong the bottom. Turtles en-tangled in the nets generally remained at the water's surface until removed.

Turtle nets were usually deployed on Monday mornings and retrieved on Friday afternoons. During periods of deployment, the nets were inspected for captures by ABI personnel at least twice each day (mornings and afternoons). Additionally, St. Lucie Plant personnel checked the nets periodically, and ABI was notified immediately if a capture was observed. ABI's sea turtle specialists were on call 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a day to retrieve captured turtles from the plant.

The A1A barrier net is used to confine turtles to the easternmost section of the in-take canal, where capture techniques have been most effective. This net is constructed of large diameter polypropylene rope and has a mesh size of 30.5 cm . A cable is used

to keep the top of the net above the water's surface and the bottom is anchored by a series of heavy blocks. The net is inclined at a slope of 3:1, with the bottom positioned upstream of the surface cable. This reduces bowing in the center and minimizes the risk of a weak or injured turtle being pinned against it by currents.

Occasionally, the integrity of the barrier net has been compromised, and turtles have been able to move west of A1A. These turtles are further constrained downstream by a security intrusion barrier positioned perpendicular to the north-south arm of the canal (Figure 2) The security barrier also consists of 30.5 cm mesh, but the net is con-

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structed of heavy chain links rather than rope.

Prior to the completion of the security intrusion barrier in December 1986, turtles uncontained by the A1A barrier net were usually removed from the canal at the intake wells of Units 1 and 2 (Figure 2). There they were retrieved by means of large mechani-cal rakes or specially designed nets. Following construction of the security intrusion barrier, only those individuals with carapace widths less than 30.5 cm were able to reach the intake wells. Thus, as required, tangle nets were set west of A1A to capture turtles larger than 30.5 cm.

In addition to ABI's netting activities, formal daily inspections of the intake canal were made to determine the numbers, locations and species of turtles present. Oc-casionally, turtles were observed in areas where they could be hand captured. Surface observations were augmented with periodic underwater inspections using SCUBA, particularly in and around the A1A barrier net and security intrusion barrier. Several turtles were hand captured during these dives.

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Regardless of capture method, all turtles removed from the canal were identiTied to species, measured, weighed, tagged, and examined for overall condition (wounds, abnormalities, parasites, etc.). Healthy turtles were released back into the ocean the same day of capture. Sick or injured turtles were treated and occasionally held for ob-servation prior to release. When treatment was warranted, injections of antibiotics and vitamins were administered by a local veterinarian. Resuscitation techniques were used if a turtle was found that appeared to have died recently. Beginning in 1982, necrop-sies were conducted on dead turtles found in fresh condition; no necropsies were per-formed during 1989.

Since 1982, blood samples have been collected and analyzed to determine the sex of immature turtles. Blood was removed from the paired dorsal cervical sinuses of sub-ject turtles using the technique described by Owens and Ruiz (1980). The samples were maintained on ice and later centrifuged for 15 minutes to separate cells and serum.

Sex determinations were subsequently made by researchers at Texas A 8 M Univer-sity using radioimmunoassay for serum testosterone (Owens et al., 1978).

Florida Power & Light Company and Applied Biology; Inc. continued to assist other sea turtle researchers in 1989. Data, specimens and/or assistance have been given to the Florida Department of Natural Resources, National Marine Fisheries Service, US Fish and Wildlife Service, US Army Corps of Engineers, Smithsonian Institution, South Carolina Wildlife and Marine Resources Division, Center for Sea Turtle Research (University of Florida), Texas A 8 M University, University of Rhode Island, University of South Carolina, University of Illinois, University of Central Florida, University of Geor-gia, Virginia Institute of Marine Science and the Western Atlantic Turtle Symposium.

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Studies t Evaluate and or Miti ate Intake Entra ment A program that assessed the feasibility of using light and/or sound to deter turtles from entering the St. Lucie Plant intake structures was conducted in 1982 and 1983 and completed in January 1984. As required, test results and evaluations were written up and a presentation was made to the NRC, National Marine Fisheries Service and the Florida Department of Natural Resources on 11 April 1984. Requirement 4.2.2 of the NRC's St. Lucie Unit 2 Appendix B Environmental Protection Plan is considered completed with submission of deterrent study findings.

RESULTS AND DISCUSSION Nestin Surve Distribution of Lo erhead N st Al n Hutchinson Island When sea turtle nesting surveys began on Hutchinson Island, nine 1.25-km-long survey areas were used to estimate loggerhead nesting activity for the entire island.

Since 1981, all 36 1-km-long segments comprising the island's coastline have been surveyed. Regardless of technique, loggerhead nest densities have shown con-siderable annual variation within individual survey areas (Figures 4 and 5). Yet, the annual spatial distribution of those nests among survey areas has produced a rather uniform gradient, nest densities consistently increasing from north to south (ABI, 1987).

The gradient appears to be linear when only the nine 1.25-km-long survey areas are used (Figure 4), but becomes non-linear when all 36 1-km-long survey areas are in-cluded in the analysis (Figure 5). During 1989 the distribution of loggerhead nests along 14

the island followed the same general pattern as previously reported, nest densities in-creasing abruptly from north to south along the northern portion of the island, reach-ing maximum densities in central survey areas and then decreasing slightly toward the southern portion of the island (I=igure 5).

In the past, the pronounced gradient observed on the northern end of the island was occasionally influenced by physical processes occurring there; periods of heavy accretion reduced the gradient, while periods of erosion accentuated it (Worth and Smith, 1976; Williams-Walls et al., 1983). However, during recent years no consistent relationship was apparent when field observations of beach widths were compared to the spatial distribution of nests along the island (ABI, 1987). Thus, even though beach dynamics may sometimes affect the selection of nesting sites by loggerhead turtles, other factors must also contribute to the selection process. Offshore bottom contours, spatial distribution of nearshore reefs, type and extent of dune vegetation, and degree of human activity on the beach at night have been identified as some of the factors af-fecting nesting (Caldwell, 1962; Hendrickson and Balasingam, 1966; Bustard, 1968; Bustard and Greenham, 1968; Hughes, 1974; Davis and Whiting, 1977; Mortimer, 1982). Relationships between spatial nesting patterns and specific environmental con-ditions are often difficult to establish because of the interrelationship of the factors in-volved.

Not all ventures onto the beach by a female turtle culminate in successful nests.

These 'Valse crawls" (non-nesting emergences) may occur for many reasons and are commonly encountered at other rookeries (Baldwin and Lofton, 1959; Schulz, 1975; Davis and Whiting, 1977; Talbert et al., 1980; Raymond, 1984). Davis and Whiting 15

l (1977) suggested that relatively high percentages of false crawls may reflect disturban-ces or unsatisfactory nesting beach characteristics. Therefore, certain factors may af-fect a turtle's preference to emerge on a beach, while other factors may affect a turtle' tendency to nest after it has emerged. An index which relates the number of nests to the number of false crawls in an area is useful in estimating the post-emergence suitability of a beach for nesting. In the present study this index is termed "nesting suc-cess" and is defined as the percentage of total emergences that result in nests.

Historically, the pattern of loggerhead emergences on the island has generally paral-leled the distribution of nests (ABI, 1987, 1988), and this same trend was apparent in 1989 (Figure 6). In contrast, nesting success by loggerheads along the island has typi-cally lacked gradients (Figure 7). Thus, the relatively high numbers of loggerhead nests usually observed along the southern half of the island have resulted primarily from more turtles coming ashore in that area rather than from more preferable nesting conditions being encountered by the turtles after they emerged.

Hughes (1974) and Bustard (1968) found that loggerheads preferred beaches ad-jacent to outcrops of rocks or subtidal reefs. Williams-Walls et al. (1983) suggested that the nesting gradient on Hutchinson Island may be influenced by the offshore reefs if female turtles concentrate on the reefs closest to the beach to rest or feed, The proximity of offshore reefs would put the greatest concentration of turtles near the southern half of the island where coincidentally nesting is highest.

Loggerhead nesting densities during 1989 were generally within the range of values previously recorded (Figures 4 and 5). The most conspicuous exceptions occurred on 16

I the northern half of the island where nesting was relatively high compared to previous years. There were no apparent changes in the physical characteristics of the beach that would account for this increase in nesting, Rather, it may be related to a decrease inhuman activity on the beach at night. Historically, nighttime vehicle use ofthe beaches has been extensive on the northern half of the island. However, between the 1988 and 1989 nesting seasons, successful blockage of many access points resulted in a forty percent reduction in this activity. If the lights, movements and noise associated with off-road vehicles previously deterred turtles from emerging to nest (see Hendrickson, 1958), a reduction in vehicle use during 1989 would account for record high emergence and nesting rates on the northern half of the island (Figures 5 and 6).

Relatively low nesting in Area F suggests that factors other than vehicle traffic con-tinued to deter turtles from nesting in that area. As previously reported (ABI, 1988, 1989), reduced nesting in Area F may be related to the removal of beachfront vegeta-tion prior to the 1987 nesting season. Additionally, extensive accumulations of shell and rock material along this section of beach during 1989 may have deterred turtles from nesting after they emerged and may explain the record low nesting success in this area (Figure 7).

Record low nesting success was also documented in Area L. The most notable change in this section of beach was an increase in the number of dead Australian pines that had fallen on the beach since the end of the 1988 nesting season. These fallen trees act as obstacles to turtles as they crawl up the beach to nest, When a turtle en-counters such an obstacle, it usually returns to the ocean without nesting.

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I On the southern half of the island, loggerhead nesting was within the range of pre-viously recorded values in all but one area (Area E@. Record low nesting in Area EE during 1989 was apparently attributable to conditions encountered by turtles after they emerged since the number of emergences were not low when compared to previous years. This is confirmed by the record low nesting success in this area during 1989.

Beach conditions which would account for such a decrease in nesting success could not be identified; however, human activity on the beach cannot be ruled out since this area is backed by a large resort and a public beach.

Nesting surveys on Hutchinson Island were initiated in response to concerns that the operation of the St. Lucie Plant might negatively impact the local sea turtle rookery.

Previous analysis, using log-likelihood tests of independence (G-test; Sokal and Rohlf, 1981) demonstrated that the construction of the plant's offshore intake and discharge structures significantly reduced nesting at the plant site during construction years 1975, 1981, 1982 and 1983 (Proffitt et al., 1986; ABI, 1987). However, nesting at the plant consistently returned to levels similar to or greater than those at a control site in years following construction (Figure 8). Thus, power plant operation exclusive of in-take/discharge construction had no apparent effect on nesting.

Data collected through 1989 have shown no long-term reduction in loggerhead nest densities, total emergences or nesting success in either the nine 1.25-km-long survey areas or the 36 1-km-long survey areas (Table 1; Figure 9).

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Estimates of Total Lo erhead Ne tin on Hutchinson Island Various methods were used during surveys prior to 1981 to estimate the total num-ber of loggerhead nests on Hutchinson Island based on the number of nests found in the nine 1.25-km-long survey areas (Gallagher et al., 1972; Worth and Smith, 1976; ABI, 1980a). Each of these methods were subsequently found to consistently overes-timate island totals (ABI, 1987). Since whole-island surveys began in 1981, it has been possible to determine the actual proportion of total nests deposited in the nine areas.

This has then allowed extrapolation from the nine survey areas to the entire island for years prior to 1981.

From 1981 through 1989 the total number of nests in the nine areas varied from 33.1 to 35.6 percent of the total number of nests on the island (Table 1). This is slight-ly higher than the 31.3 percent which would be expected based strictly on the propor-tion of linear coastline comprised by the nine areas. Using the nine-year mean of 34.0 percent, estimates of the total number of nests on Hutchinson Island can be calculated by multiplying the number of nests in the nine areas by 2.94. This technique, when ap-plied to the nine survey areas during the nine years in which the entire island was sur-veyed, produced whole-island estimates within five percent of the actual number of nests counted. Because the proportion of nests recorded in the nine survey areas remained relatively constant over the last nine years, this extrapolation procedure should provide a fairly accurate estimate of total loggerhead nesting for years prior to 1981.

I It is clear that loggerhead nesting activity on Hutchinson Island fluctuates con-siderably from year to year (Table 1). Annual variations in nest densities also are com-mon at other rookeries (Hughes, 1976; Davis and Whiting, 1977; Ehrhart, 1980) and may result from the overlapping of non-annual breeding populations. During the last eight years, however, annual nest production has remained relatively high. Total nest-ing activity was greatest during 1986 when 5,483 loggerhead nests were recorded on the island. During 1989, 5,193 nests were counted. No relationships between total nesting activity and power plant operation or intake/discharge construction were indi-cated by year-to-year variations in total nesting on Hutchinson Island.

Tem oral Lo erhead Nestin Patterns The loggerhead turtle nesting season usually begins between mid-April and early May, attains a maximum during June or July, and ends by late August or early Sep-tember (ABI, 1987). Nesting activity during 1989 followed this same pattern (Figure 10).

Cool water intrusions frequently occur over the continental shelf of southeast Florida during the summer (Taylor and Stewart, 1958; Smith, 1982). Worth and Smith (1976),

Williams-Walls et al. (1983) and ABI (1982, 1983, 1984b, 1985b, 1986, 1987, 1988, 1989) suggested that these intrusions may have been responsible for the temporary declines in loggerhead turtle nesting activity previously observed on Hutchinson Island.

Similarly, a substantial decrease in nesting during mid-June 1989 was apparently due to an intrusion of cool water (Figure 10).

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Though natural fluctuations in temperature have been shown to affect temporal nest-ing patterns on Hutchinson Island, there has been no indication that power plant opera-tion has affected these temporal patterns (ABI, 1988) ~

Pr dation on Lo rh a T rtle Nests Since nest surveys began in 1971, raccoon predation probably has been the major cause of turtle nest destruction on Hutchinson Island. Researchers at other locations have reported raccoon predation levels as high as 70 to nearly 100 percent (Davis and Whiting, 1977; Ehrhart, 1979; Hopkins et al., 1979; Talbert et al., 1980). Raccoon preda-tion of loggerhead turtle nests on Hutchinson Island has not approached this level during any study year, though levels for individual 1.25-km-long areas have been as high as 80 percent. Overall predation rates for survey years 1971 through 1977 were between 21 and 44 percent, with a high of 44 percent recorded in1973. A pronounced decrease in raccoon predation occurred after 1977, and overall predation rates for the nine areas have not exceeded 10 percent since 1979. A decline in predation rates on Hutchinson Island has been variously attributed to trapping programs, construction activities, habitat loss and disease (Williams-Walls et al., 1983; ABI, 1987).

During 1989, eight percent (423) of the loggerhead nests (n =5,193) on the island were depredated by raccoons. As in previous years (ABI, 1989), predation of turtle nests was primarily restricted to the most undeveloped portion of the island (i.e., Areas E through S; Figure 11).

Ghost crabs have been reported by numerous researchers as important predators of sea turtle nests (Baldwin and Lofton, 1959; Schulz, 1975; Diamond, 1976; Fowler, 21

1979; Hopkins et al ~, 1979; Stancyk, 1982). Though turtle nests on Hutchinson Island probably have been depredated by ghost crabs since nesting surveys began in 1971, this source of nest destruction did not become apparent until 1983. Quantification of ghost crab predation was initiated the same year.

Overall predation rates by ghost crabs have varied from 0.2 to 2.1 percent from 1983 - 1988 (ABI, 1989). During 1989, 0.1 percent (6) of the loggerhead nests (n = 5,193) on the island were destroyed by ghost crabs (Figure 11). Nests destroyed by a combination of raccoon and ghost crab predation have been included as raccoon predations in previous discussions. When these combination predations are included as crab predations, the overall predation rates by ghost crabs range from 0.4 to 3.2 percent. During 1989, 0.4 percent (23 nests) were destroyed by either ghost crabs or a combination of ghost crabs and raccoons.

Green and Leatherback Turtle Nestin Green and leatherback turtles also nest on Hutchinson Island, but in fewer numbers than loggerhead turtles. Prior to 1981, both survey (nine 1.25-km-long sections) and inter-survey areas were monitored for the presence of green and leatherback nests.

Thirty-one kilometers of beach from Area 1 south to the St. Lucie Inlet were included in that effort. During whole-island surveys from 1981 through 1989, only two of 170 leatherback nests and only five of 469 green nests were recorded on the five kilometers of beach north of Area 1. Therefore, previous counts of green and leatherback nests within the 31 kilometers surveyed were probably not appreciably different from total densities for the entire island. Based on this assumption, green and leatherback nest 22

densities may be compared among all survey years, except 1980, when less than 15 kilometers of beach were surveyed.

Prior to 1989, the number of nests observed on the island ranged from 5 to 74 for green turtles and from 1 to 33 for leatherbacks (Figure 12). During the 1989 survey, 45 green turtle and 36 leatherback turtle nests were recorded on Hutchinson Island.

Temporal nesting patterns for these species differ from the pattern for loggerhead turtles. Green turtles typically nest on Hutchinson Island from mid-June through the first or second week of September. During 1989, green turtles nested from 15 June through 23 September. Leatherback turtles usually nest on the island from mid-April through early to mid-July. During 1989 this species nested from 30 March through 17 July.

0 Considerable fluctuations in green turtle nesting on the island. have occurred among survey years (Figure 12). This is not unusual since there are drastic year-to-year fluc-tuations in the numbers of green turtles nesting at other breeding grounds (Carr et al.,

1982). Despite these fluctuations, green turtle nesting has remained relatively high during the last eight years (1982 through 1989) and may reflect an increase in the num-ber of nesting females in the Hutchinson Island area. During 1989, green turtles nested most frequently along the southern half of the island. This is consistent with results of previous surveys.

Leatherback turtle nest densities have remained low on Hutchinson Island; however, increased nesting during recent years (Figure 12) may reflect an overall increase in the 23

number of nesting females in the Hutchinson Island area. During 1989, leatherback turtles primarily nested on the southern half of the island.

Intake Canal Monitorin Entrainment of sea turtles at the St. Lucie Plant has been attributed to the presumed physical attractiveness of the offshore structures housing the intake pipes rather than to plant operating characteristics (ABI, 1980b and 1986). Even when both units are operating at full capacity, turtles must actively swim into the mouth of one of the intake pipes before they encounter current velocities sufficiently strong to effect entrainment.

Consequently, a turtle's entrapment relates primarily to the probability that it will detect and subsequently enter one of the intake structures. Assuming that detection distan-ces do not vary appreciably over time and that all turtles (or a constant proportion) are equally attracted to the structures, capture rates will vary proportionally to the number of turtles occurring in the vicinity of the structures. If this assumption is true, data from the canal capture program should reflect natural variability in the structure of the popula-tion being sampled.

Relative Abundance and Tem oral Distribution During 1989, 133 sea turtle captures took place in the intake canal of the St. Lucie Plant (Table 2). All five species of sea turtles occurring in coastal waters of the southeastern United States were represented in the catches, including 111 logger-heads, 17 greens, 1 leatherback, 2 hawksbills and 2 Kemp's ridleys. Since intake canal monitoring began in May 1976, 1,741 loggerhead (including 89 recaptures), 286 green 24

(including 1 recapture), 9 leatherback, 8 hawksbill and 17 Kemp's ridley captures have been reported from the St, Lucie Plant.

Annual catches of loggerheads increased steadily from a low of 33 in 1976 (partial year of plant operation and monitoring) to 172 in 1979 (Figure 13). After declining be-tween 1979 and 1981, yearly catches of loggerheads again rose steadily, reaching a high of 195 during 1986. Captures have been in decline since 1986, decreasing over 40 percent during the last three years.

Two offshore intake structures were in place prior to Unit 1 start-up in 1976; the third and largest structure was installed during 1982-1983. Even though all three structures are in relatively close proximity, the addition of another pipe may have increased the probability of a turtle being entrained. Because this change cannot be quantified, data collected prior to 1982 may not be comparable with that collected after 1983.'Addition-ally, the influence of the construction itself on sea turtle entrainment during 1982 and 1983 is unknown. With these considerations in mind, neither a long-term increase nor decrease in the number of loggerheads captured at the St. Lucie Plant can be inferred from the data.

During 1989, the monthly catch of loggerheads ranged from 2 (September and December) to 21 (July), with a monthly mean of 9.3 (+6.4; Table 3). The number of captures between April and August were average or above average, while captures throughout the remainder of the year were generally lower than average (Figure 14).

Over the entire monitoring period, monthly catches have ranged from 0 to 39; the greatest number of captures occurred during January 1983.

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When data from all full years of monitoring (1977-1989) were combined, the highest number of loggerhead captures occurred in January (12.5 percent); fewest captures were recorded in November and December (Table 3). However, monthly catches have shown considerable annual variability. Months having relatively low catches one year often have had relatively high catches in another.

Catches of green turtles also have varied widely among years, ranging from 0 in 1976 (partial year of sampling) to 69 in 1984 (Table 4). During 1989, 17 individuals were captured. The average annual catch of green turtles, excluding 1976, was 22.0 (+18.7).

Although highly variable, annual capture data for green turtles suggest a long-term in-crease in the number of individuals inhabiting the nearshore coastal area adjacent to

)4 the plant (Figure 13). Again, however, the influence of the addition of a third intake pipe in 1982 on these data is not known.

Green turtles have been caught during every month of the year, with average month-ly catches for all years combined ranging from 0.4 in September to 7.2 in January (Table 4). However, seasonal abundance patterns of greens are much more pronounced than for loggerheads, about 80 percent of all captures occurring between November and April. During 1989, the largest number of greens (6) were captured in March. The most greens ever caught in one month was 37 in January 1984.

Catches of leatherbacks, hawksbills and Kemp's ridleys have been infrequent and scattered throughout the 14 year study period (Table 2). Each species has shown rather'pronounced seasonal occurrences; all but two of the nine leatherbacks were collected between February and May, seven of the eight hawksbills were collected 26

4 between June and September, and all but two of the 17 Kemp's ridleys were caught between November and April ~

iz -Clas Distrib ti n Although several straight-line and curved measurements were recorded for turtles removed from the intake canal, only one straight-line measurement has been used in analyses presented here. Straight-line carapace length (SLCL) was measured from the precentral scute to the notch between the postcentral scutes (minimum carapace length of Pritchard et al., 1983).

To date, loggerheads removed from the intake canal have ranged in length (SLCL) from 40.4 to 112.0 cm (x = 66.3 + 13.3 cm) and in weight from 10.9 kg to 160.6 kg (Figures 15 and 16). About 71 percent of all loggerheads captured were 70 cm or less in length and weighed less than 50 kilograms.

A carapace length of 70 cm approximates the smallest size of nesting loggerhead females observed along the Atlantic east coast (Hirth, 1980). However, adults can only be reliably sexed on external morphological characteristics (e.g., relative tail length) after obtaining a length of about 80 cm. Based on these divisions, data were segregated into three groups: juvenile/sub-adults (<70 cm; the demarcation between these two components is not well established in the literature), adults (>80 cm) and transitional (70-80 cm). The latter group probably includes some mature and some immature in-dividuals. Of the 1,666 captures for which length data were collected, 71 percent were juveniles/sub-adults, the majority of these measuring between 50 and 70 cm SLCL (Table 5). Adults accounted for about 18 percent of all captures, the remaining 11 27

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percent comprised of animals in the transitional size class. Similar size-frequency dis-tributions, indicating a preponderance of juveniles, have been reported for the Mosquito/Indian River Lagoon (Mendonca and Ehrhart, 1982), the Canaveral ship channel (Henwood, 1987), and Georgia and South Carolina (Hillestad et al., 1982).

These data suggest that coastal waters of the southeastern United States constitute an important developmental habitat for Qgr~ett.~ gargtta.

Seasonal patterns of abundance for various size classes indicated that juveniles and sub-adult loggerheads were slightly more abundant during the winter than at other times of the year (Table 5). About 36 percent of juvenile/sub-adult loggerheads were captured between January and March. Abundances decreased in spring and remained relatively constant during the summer and early fall before decreasing again to lowest levels in November and December. The seasonal distribution of adult loggerheads was much more pronounced, 58 percent of all captures occurring between June and August. This represents the period of peak nesting on Hutchinson Island. If other nest-ing months are included (May and September), 75 percent of all adults were captured during the nesting season.

Green turtles removed from the intake canal over the entire study period ranged in size from 20 to 108 cm SLCL (x = 35.8 + 14.4 cm) and 0.9 kg to 177.8 kg (Figures 17 and 18). Nearly all (96 percent) were juveniles or sub-adults. About 80 percent were 40 cm or less in length, and 67 percent weighed 5 kilograms or less. These immature turtles exhibited distinct winter pulses suggesting migratory behavior (Table 4).

However, some immature green turtles were present throughout the year. To date, only eight adult green turtles (SLCL >83 cm; Witherington and Ehrhart, 1989) have 28

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been removed from the canal; all were captured during or shortly after the nesting season.

The eight hawksbills removed from the canal ranged in size from 34.0 to 70.0 cm SLCL(x = 46.2+ 12.9 cm) and in weight from 6.4 to 52.2 kg (x = 17.3 + 16.6 kg).

All but one were juveniles (SLCL (63 cm; Witzell, 1983). Similarly, all but one of the 17 Kemp's ridleys captured at the St. Lucie Plant were juveniles (SLCL (60.0 cm; Hirth, 1980). Carapace lengths for the ridleys ranged from 27.0 to 62.0 cm SLCL (x = 36.1

+ 9.7 cm) and weights from 3.2 to 31.8 kg (x = 8.0 + 8.1 kg). The nine leatherbacks removed from the canal ranged in length from 112.5 to 150.0 cm, and at least seven were adults (SLCL )121 cm; Hirth, 1980). The largest leatherback for which an ac-curate weight was obtained, a female with a curved carapace length of 158.5 cm, weighed 334.8 kg.

Sex Ratios Since intake canal monitoring began in 1976, 297 adult loggerheads have been sexed. The smallest was 75.5 cm in length and was observed nesting on Hutchinson Island shortly after her capture in the canal. Females predominated males by a ratio of 5.6:1.0, which significantly departs from a 1:1 ratio (X, P(0.05). Consequently, tem-poral patterns in the number of adult loggerhead captures are heavily influenced by the numbers of females present. When sexes were separated, it is evident that males were relatively evenly distributed among months, whereas over 80 percent of the females were taken during the nesting season (May through September; Figure 19).

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The number of adult female loggerheads captured at the St. Lucie Plant has in-creased steadily over the last seven years. Prior to 1983, an average of 6.5 adult females

(+ 3.8; range = 1-12) were entrapped each year, whereas since then, an average of 30.1 females per year (+ 11.6; range = 12-45) were captured. This increase cor-responds to a general rise in loggerhead nesting activity near the plant (Figure 20). In-creased nearshore movement associated with nesting increases the probability of a turtle detecting one of the intake structures and hence the probability of entrainment.

Although the addition of the third offshore intake structure in 1982 may have accounted for some of the increase in the number of adults entrained each year, the continued rise since 1982 suggests a genuine increase in the number of females occurring in the vicinity of the plant.

Between September 1982 and December 1986, 267 individual juvenile and sub-adult loggerhead turtles captured in the canal were sexed by Texas A & M University re-searchers using a bioimmunoassay technique for blood serum testosterone. As pre-viously reported, females outnumbered males by a ratio of 2.3:1.0 (ABI, 1989). These findings are consistent with those reported for samples taken from the Cape Canaveral ship channel (1.7:1.0) and the Indian River Lagoon (1.4:1.0), where sex ratios are also significantly skewed in favor of females (Wibbels et al., 1984). Blood samples collected since 1986 are currently being analyzed and these results will provide a valuable tool for assessing temporal variability in the sex ratios of the local loggerhead population.

Of the eight adult green turtles captured since monitoring began, six were males and two were females. Six immature green turtles have been sexed through blood work; all have been females. Of the six adult leatherback turtles for which sex was recorded, 30

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three were females and three were males. The adult hawksbill and Kemp's ridley were both females. No sex information exists for juveniles of these species.

Ca ture Efficiencies Capture methodologies evolved over the first several years of intake canal monitor-ing as net materials, configurations and placement were varied in an effort to minimize sea turtle entrapment times. Concurrently, alternative capture techniques were evaluated and potential deterrent systems tested in the laboratory. During this period, capture efficiencies varied in relation to netting effort and the effectiveness of the sys-tems deployed.

A capture/recapture study conducted in the intake canal between October 1980 and January 1981 indicated that most turtles confined between the A1A bridge and the intake headwalls were captured within two weeks of their entrainment (ABI, 1983).

Based on more recent formal daily inspections, it appears that capture efficiencies have further improved. Most turtles entering the canal are now caught within a few days of first sighting, and in many instances, turtles have been caught in the tangle nets without any prior sighting, suggesting residency times of less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Better utilization of currents and eddies, adjustments to tethering lines and multi-net deployments have contributed to reduced entrapment times.

Entrapment times may be extended for turtles swimming past the A1A barrier net (ABI, 1987). Occasionally, the top of the net has been submerged or the anchor cable pulled free from the bottom, allowing larger turtles to pass; turtles with carapace widths less than about 30.5 cm can swim through the large mesh. Because capture efforts

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west of the A1A bridge have generally been less effective than those near the intake headwalls, most turtles breaching the barrier net were not caught until they entered the intake wells of Units 1 and 2. Since the canal capture program began, about 14 per-cent of all turtles entrapped in the canal have been removed from the intake wells. Be-cause of their relatively small sizes, a greater proportion of greens (47.9 percent) reached the plant than loggerheads (8.1 percent) ~

After completion of the security intrusion barrier in December 1986, turtles larger than 30.5 cm in carapace width were prevented from reaching the intake wells. During 1989, only six loggerheads (5.4 percent of all loggerhead captures) breached the A1A barrier net. Four of these were removed from the canal at the intrusion barrier, while the other two were captured further upstream. By comparison, a total of six green and one Kemp's ridley (35 and 56 percent, respectively, of total captures) circumvented the A1A barrier net during 1989. All of these were removed at the plant's intake wells.

Relative Condition Turtles captured alive in the intake canal of the St. Lucie Plant were assigned a rela-tive condition based on weight, activity, parasite infestation, barnacle coverage, wounds, injuries and any other abnormalities which might have affected overall well-being (Table 6). During 1989, 89.2 percent (99) of all loggerheads found in the canal were alive and in good to excellent condition. Only 7.2 percent (8) of loggerhead cap-tures involved individuals in fair or poor condition; 3.6 percent (4) of the loggerheads removed from the canal were dead.

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Of the 17 green turtles removed from the intake canal during 1989, all but one (94.1 percent) were in good to excellent condition. The remaining individual was dead when recovered. Both hawksbills, the leatherback and one of the two Kemp's ridleys were in good to excellent condition when captured. The other Kemp's ridley was in poor condition.

Over the entire monitoring period, about 72 and 79 percent, respectively, of all log-gerhead and green captures have involved turtles in good to excellent condition (Table

4) 6). Captures of individuals in fair to poor condition have occurred about 20 percent of the time for loggerheads and 13 percent of the time for greens. All of the hawksbills and all but one leatherback have been removed from the canal in good to excellent condition, while about half of the Kemp's ridleys have fallen into these categories.

o Relative condition ratings can be influenced by a number of factors, some related and others unrelated to entrainment and/or entrapment in the intake canal. Ratings of good to excellent indicate that turtles have not been negatively impacted by their entrap-ment in the canal, at least as evidenced by physical appearance. Although ratings of fair or poor imply reduced vitality, the extent to which entrainment/entrapment is responsible is often indeterminable. In some instances, conditions responsible for lower ratings, such as injuries, obviously were sustained prior to entrainment.

During 1989, only five percent of all captures involved individuals with noticeable in-juries, such as missing appendages, broken or missing pieces of carapace and deep lacerations. Most of these were old, well-healed wounds. At least three loggerheads appeared to have been impacted by boat collisions as evidenced by substantial 33

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carapace damage. They were examined by a veterinarian and released the same day.

Two other loggerheads were entangled in fishing line and had sustained deep lacera-tions as a result.

~Mort iiti s During 1989, 4 loggerhead mortalities (3.6 percent of all loggerhead captures) were recorded in the intake canal. One was removed from the security intrusion barrier, one from the A1A barrier net and the other two were found floating unobstructed in the canal. Additionally, a small green turtle was found dead near the intake wells. The death of one of the loggerheads appears to have resulted either directly or indirectly from en-tanglement in monofllament fishing line. The two loggerheads removed from the con-tainment nets may have drowned, but this could not be positively established.

Over the entire 14 year monitoring period, 126 (7.2 percent) of the 1,741 logger-heads and 19 (6.6 percent) of the 286 green turtles entrapped in the canal were found dead (Table 6). Mortalities spanned the range of size classes for loggerheads (SLCL

= 47.5-103 cm), while all green turtle mortalities involved juveniles less than 41 cm in length. The four Kemp's ridley mortalities documented at the plant during 1987 and 1988 were the only deaths for this species to date; no leatherback or hawksbill mor-talities have occurred at the St. Lucie Plant.

Mortalities have been closely monitored throughout the life of the canal capture program in an attempt to assign probable causes and take appropriate corrective measures to reduce future occurrences. Previous analyses of capture data identified drowning in nets, drowning in the intake pipes during periods of reduced intake flow, 34

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injuries sustained from dredging operations and injuries sustained from the mechani-cal rakes used in the intake wells as probable mortality factors (ABl, 1987). Although difficult to quantify, the entrapment and subsequent demise of injured or sick turtles probably accounts for a portion of observed mortalities.

Most recent mortalities in the intake canal apparently resulted from drownings at the A1A barrier net and the newly constructed security intrusion barrier. A dramatic in-crease in loggerhead mortalities between 1985 and 1986 (Table 2) was thought to have been related to adjustments made to the A1A barrier net during the latter part of 1985 (ABI, 1987). Presumably, these adjustments increased the probability of a turtle drown-ing. A new barrier net installed in November 1987 apparently corrected previous problems, as only one mortality has been recorded at the A1A bridge since. That mor-tality occurred during 1989. However, it could not be determined if the loggerhead drowned as a result of entanglement in the barrier net or if it was dead before drifting into the net.

During 1989, six turtles wider than 35.0 cm breached the A1A barrier net and entered the western portion of the intake canal where capture efforts are less effective. All were loggerheads. Four were hand captured at the security intrusion barrier, while the other two were removed further upstream. Previous observations suggested that sick or in-jured turtles may be more susceptible to drowning at the intrusion barrier than healthy turtles (ABI, 1988). Of the four loggerheads recovered at the intrusion barrier during 1989, only one was dead. Similar to previous mortalities, this one involved an apparent-ly underweight individual, suggesting that it may have been in poor health at the time of entrapment.

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Reca ture Incidents Since the St. Lucie Plant capture program began, most turtles removed alive from the intake canal have been tagged and released into the-ocean at various locations along Hutchinson Island. Consequently, individual turtles can be identified as long as they retain their tags. Over the 14 year history of turtle entrapment at the St. Lucie Plant, 56 individuals (55 loggerheads and 1 green) have been removed from the canal more than once. Several other turtles with tag scars have also been removed, indicating that the actual number of recaptures may be higher.

Of the 55 individual loggerheads known to have been caught more than once, 41 were caught twice, six were caught three times, four were caught four times, two were captured six times, one was caught seven times and one was caught on nine separate occasions, yielding a total of 89 recapture incidents. Release site did not appear to have any effect on a turtle's probability of being recaptured. Turtles released both north and south of the plant returned. Recaptures also did not appear to be related to size, as both juveniles and adults were captured more than once (range of SLCL = 47-89 cm). However, the majority of recapture incidents involved juveniles and sub-adults (SLCL <70 cm).

Recapture intervals for loggerheads ranged from four to 858 days, with a mean of 161 days (+175.4 days). The only green turtle caught more than once was captured on two occasions, returning to the canal 59 days after first being released into the ocean. About 53 percent of all loggerhead recapture incidents occurred within 90 days of previous capture and 90 percent within one year (Figure 21). The average interval 36

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between first and last capture was 264 days (+322.2 days). The longest period be-tween first and last capture was 5.3 years. These data suggest that residency times of loggerheads within the nearshore habitat adjacent to the St. Lucie Plant are relatively short. Similar findings have been reported for loggerheads inhabiting the Mosquito/In-dian River Lagoons of east-central Florida (Mendonca and Ehrhart, 1982).

SUMMARY

A gradient of increasing loggerhead turtle nest densities from north to south along the northern half of Hutchinson Island has been shown during all survey years. This gradient may result from variations in beach topography, offshore depth contours, dis-tribution of nearshore reefs, onshore artificial lighting and human activity on the beach at night. Low nesting activity in the vicinity of the power plant during 1975 and from 1981 through 1983 was attributed to construction of power plant intake and discharge systems. Nesting returned to normal or above normal levels following both periods of construction. Power plant operation, exclusive of intake/discharge construction, has had no significant effect on nest densities.

There have been considerable year-to-year fluctuations in loggerhead nesting ac-tivity on Hutchinson Island from 1971 through 1989. Fluctuations are common at other rookeries and may result from overlapping of non-annual breeding populations.

Despite these fluctuations, loggerhead nesting activity has remained relatively high during the last eight years. No relationship between total nesting on the island and power plant operation or intake/discharge construction was indicated.

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Temporary declines in loggerhead nesting activity have been attributed to cool water intrusions that frequently occur over the continental shelf of southeast Florida. Though temporal nesting patterns of the Hutchinson Island population may be influenced by natural fluctuations in water temperature, no significant effects due to power plant operation have been indicated.

Since nesting surveys began in 1971, raccoon predation was considered the major cause of turtle nest destruction on Hutchinson Island. From 1971 through 1977, over-all predation rates in the nine survey areas were between 21 and 44 percent. However, a pronounced decrease in raccoon predation occurred after 1977, and overall preda-tion rates in the nine survey areas have not exceeded ten percent since 1979.

Decreased predation by raccoons probably reflects a decline in the raccoon popula-tion.

During 1989, 45 green turtle and 36 leatherback turtle nests were recorded on Hutchinson Island. Green turtle nesting activity exhibited considerable annual fluctua-tions, as has been recorded at other rookeries, but has remained relatively high during the last seven years. Leatherback turtle nest densities have remained low on Hutchin-son Island; however, increased nesting during recent years may reflect an overall in-crease in the number of nesting females in the Hutchinson Island area.

During 1989, 111 loggerheads, 17 green turtles, 1 leatherback; 2 hawksbills and 2 Kemp's ridleys were removed from the St. Lucie Plant intake canal Since monitoring

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began in May 1976, 1,741 loggerhead, 286 green, 9 leatherback, 8 hawksbill and 17 Kemp's ridley turtles have been captured. Over the life of the monitoring program, 38

l annual catches for loggerhead turtles have ranged from 33 in 1976 (partial year of plant operation and monitoring) to a high of 195 in 1986. Yearly catches of green turtles have ranged from 0 in 1976 to 69 in 1984. Differences in the number of turtles entrapped during different years and months are attributed to natural variation in the occurrence of turtles in the vicinity of the offshore intake structures, rather than to any influence of Y

the plant itself.

Size-class distributions of loggerhead turtles removed each year from the canal have consistently been predominated by juveniles and sub-adults between 50 and 70 cm in straight line carapace length. Most green turtles entrapped in the canal (about 80 per-cent) were juveniles 40 cm or less in length. For both species, the largest number of captures for all years combined occurred during the winter, but these seasonal peaks were much more pronounced for green turtles. Sex ratios of both adult and immature loggerheads caught in the canal continued to be biased towards females.

During 1989, about 89 percent of all loggerheads and green turtles removed from the canal were categorized by physical appearance as being in good to excellent con-dition. Over the entire 14 year monitoring period, 72 and 79 percent, respectively, of all loggerhead and green turtle captures have involved individuals in these categories; 20 percent of the loggerheads and 13 percent of the green turtles removed from the canal have been in fair or poor condition.

Only five percent of the turtles removed from the intake canal during 1989 had sub-stantial injuries. It appeared that most of these injuries were sustained prior to entrap-ment. Once in the canal, turtles confined east of A1A usually had very brief residency 39

4 times and thus the relative condition of most turtles was not affected by their entrap-ment. During 1989, 6 loggerheads, 6 green turtles and 1 Kemp's ridley swam west of the A1A bridge. Most of the loggerheads were retrieved at the security intrusion bar-rier. All of the green turtles and the Kemp's ridley were removed from the canal at the intake wells. Since monitoring began, about 8 percent of all loggerhead and 48 per-cent of all green turtle captures have occurred at the intake wells.

During 1989, one green and four loggerhead mortalities were recorded for the in-take canal. Two of these deaths appeared to have resulted from drowning, while a third may have resulted from entanglement in monofilament fishing line.

Since intake canal monitoring began in 1976, 7.2 percent of the loggerheads and 6.6 percent of the green turtles removed from the canal were dead. The four Kemp's ridley mortalities in 1987 and 1988 were the only deaths recorded for this species since monitoring began. All of the leatherbacks and hawksbills entrapped in the intake canal at the St. Lucie Plant have been captured alive and released into the ocean.

5 l

L1TERATURE CITED ABI (Applied Biology, Inc). 1977. Ecological monitoring at the Florida Power & Light Co. St.

Lucie Plant, annual report 1976. Volumes I and II. AB~. Prepared by Applied Biology, Inc. for Florida Power & Light Co., Miami.

. 1978. Ecological monitoring at the Rorida Power & Light Co. St. Lucie Plant, annual report 1977. Volumes I and II. AB-101 Prepared by Applied Biology, Inc. for

~

Florida Power & Light Co., Miami.

. 1979. Florida Power & Light Company, St. Lucie Plant annual non-radiologi-cal environmental monitoring report 1978. Volumes II and III, Biotic monitoring. AB-177. Prepared by Applied Biology, tnc. for Florida Power & Light Co., Miami.

. 1980a. Florida Power & Light Company, St. Lucie Plant annual non-radiologi-cal environmental monitoring report 1979. Volumes II and III, Biotic monitoring. AB-244. Prepared by Applied Biology, Inc. for Florida Power 8 Light Co., Miami.

1 . 1980b. Turtle entrainment deterrent study. AB-290. Prepared by Applied Biology, Inc. for Florida Power & Light Co., Miami.

. 1981a. Successful relocation of sea turtle nests near the St. Lucie Plant, Hutchinson Island, Florida. AB-317. Prepared by Applied Biology, Inc. for Florida Power

& Light Co., Miami.

. 1981b. Florida Power & Light Company, St. Lucie Plant annual non-radiologi-cal environmental monitoring report 1980. Volumes II and III, Biotic monitoring. AB-324. Prepared by Applied Biology, lnc. for Florida Power & Light Co., Miami.

. 1981c. Proposed St. Lucie Plant preoperational and operational biological monitoring program - August 1981. AB-358. Prepared by Applied Biology, Inc. for Florida Power & Light Co., Miami.

. 1982. Florida Power & Ught Company, St. Lucie Plant annual non-radiologi-cal environmental monitoring report 1981. Volumes II and III, Biotic monitoring. AB-379. Prepared by Applied Biology, Inc. for Florida Power & Light Co., Miami.

. 1983. Florida Power & Light Company, St. Lucie Plant annual non-radiologi-cal aquatic monitoring report 1982. Volumes I and II AB-442. Prepared by Applied Biol-

~

ogy, Inc. for Florida Power & Light Co., Miami.

41

Bl (Applied Biology, lnc.). 1984a. Florida Power & Light Company, St. Lucie Plant annual non-radiological environmental monitoring report 1983. Volumes I and II. AB-530.

Prepared by Applied Biology, Inc. for Florida Power & Light Co., Miami.

. 1984b. Florida Power & Light Company, St. Lucie Unit 2 annual environ-mental operating report 1983. AB-533. Prepared by Applied Biology, Inc. for Florida Power & Light Co., Miami.

. 1985a. Florida Power & Light Company, St. Lucie Plant annual non-radiologi-cal environmental monitoring report 1984. AB-553. Prepared by Applied Biology, Inc.

for Florida Power & Light Co., Juno Beach.

. 1985b. Florida Power & Light Company, St. Lucie Unit 2 annual environ-mental operating report 1984. AB-555. Prepared by Applied Biology, Inc. for Florida Power & Light Co., Juno Beach.

. 1986. Florida Power & Light Company, St. Lucie Unit 2 annual environmen-tal operating report 1985. AB-563. Prepared by Applied Biology, Inc. for Florida Power

& Light Co., Juno Beach.

. 1987. Florida Power & Light Company, St. Lucie Unit 2 annual environmen-tal operating report 1986. AB-579. Prepared by Applied Biology, Inc. for Florida Power

& Light Co., Juno Beach.

. 1988. Florida Power & Light Company, St. Lucie Unit 2 annual environmen-tal operating report 1987. AB-595. Prepared by Applied Biology, Inc. for Florida Power

& Light Co., Juno Beach.

. 1989. Florida Power & Light Company, St. Lucie Unit 2 annual environmen-tal operating report 1988. AB-596. Prepared by Applied Biology, Inc. for Florida Power

& Light Co., Juno Beach.

Baldwin, W.P., Jr. and J.P. Lofton, Jr. 1959. The loggerhead turtles of Cape Romain, South Carolina. Previously unpublished manuscript abridged and annotated by D.K. Caldwell, without the authors. In D.K. Caldwell and A. Carr, coordinators, The Atlantic logger-head sea turtle, Caretta caretta caretta (L), in America. Bulletin of the Florida State Museum, Biological Sciences, 4(10):319-348.

Bellmund, S., M.T. Masnik and G. LaRoche. 1982. Assessment of the impacts of the St. Lucie 2 Nuclear Station on threatened or endangered species. US Nuclear Regulatory Com-mission, Office of Nuclear Reactor Regulation.

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l ustard, H.R. 1968. Protection for a rookery: Bundaberg sea turtles. Wildlifein Australia 5:43-44.

Bustard, H.R. and P. Greenham. 1968. Physical and chemical factors affecting hatching in the green sea turtle, Chelonia ~mdas (L). Ecology 49(2):269-276.

Caldwell, D.K. 1962. Comments on the nesting behavior of Atlantic loggerhead sea turtles, based primarily on tagging returns. Quarterly Journal of the Florida Academy of Scien-ces 25(4):287-302.

Caldwell, D.K., A. Carr and LH. Ogren. 1959. Nesting and migration of the Atlantic logger-head turtle. In D.K. Caldwell and A. Carr, coordinators, The Atlantic loggerhead sea turtle Caretta caretta caretta (L), in America. Bulletin of the Florida State Museum, Biological Sciences, 4(10):295-306.

Camp, D.K., N.W. Whiting and R.E. Martin. 1977. Nearshore marine ecology at Hutchinson Island, Florida: 1971-1974. V. Arthropods. Florida Marine Research Publications 25:

1-63.

Carr, A., A. Meylan, J. Mortimer, K. Bjorndal and T. Carr. 1982. Surveys of sea turtle popula-

~ ~ ~ ~ ~ ~ ~

tions and habitats in the Western Atlantic. NOAATechnical Memorandum NMFS-SEFC-

~

~

91:1-82. ~

Davis, G.E., and M.C. Whiting. 1977. Loggerhead sea turtle nesting in Everglades National Park, Florida, U.S.A. Herpetologica 33:18-28.

id Di AW 1976.B hgti Ci I gy d ti fH k tii~l~lt a~I .~E imbricata L, on Cousin Island, Seychelles. Biological Conservation 9:199-215.

Ehrhart, LM. 1979. Reproductive characteristics and management potential of the sea turtle rookery at Canaveral National Seashore, Florida. Pages 397-399 in Linn, R.M., ed.

Proceedings of the First Conference on Scientific Research in the National Parks, 9-12 November, 1976, New Orleans, La. NPS Trans. and Proc. Ser. No. 5.

Ehrhart, LM. 1980. Threatened and endangered species of the Kennedy Space Center:

marine turtle studies. In A continuation of baseline studies for environmentally monitor-ing space transportation systems (STS) at John F. Kennedy Space Center. Contract No. NAS-10-8986. Vol. IV, NASA Report 163122. September 1980.

43

~

~

~

~

~

~

ig l

~

rnest, R.G., R.E. Martin, B.D. Peery, D.G. Strom, J.R. Wilcox and N.W. Walls. 1988. Sea turtle entrapment at a coastal power plant. Pages 270-301 in Mahadevan, K., R.K. Evans, P.

Behrens, T. Biffar and L Olsen, eds. Proceedings, Southeastern Workshop on Aquatic Ecological Effects of Power Generation. Report No. 124, Mote Marine Laboratory, Sarasota, Florida, Ernest, R.G., R.E. Martin, N.W. Walls and J.R. Wilcox. 1989. Population dynamics of sea turtles utilizing shallow coastal waters off Hutchinson Island, Florida. Pages 57-59 in Eckert, S.A., K.L Eckert and T.H. Richardson, compilers. Proceedings of the Ninth Annual Workshop on Sea Turtle Conservation and Biology. NOAA Technical Memorandum NMFS-SEFC-232.

Fowler, LE. 1979. Hatching success and nest predation in the green sea turtle, Chelonia

~mdas at Tortvgvero, Costa Rica. Ecology 60(5i:945-955.

Futch, C.R. and S.E. Dwinell. 1977. Nearshore marine ecology at Hutchinson Island, Florida:

1971-1974. IV. Lancelets and Fishes. Florida Marine Research Publications 24: 1-23.

Gallagher, R.M. 1977. Nearshore marine ecology at Hutchinson Island, Florida: 1971-1974.

II. Sediments. Florida Marine Research Publications 23: 6-24.

allagher, R.M. and M.L Hollinger. 1977. Nearshore marine ecology at Hutchinson Island,.

~

~ ~ ~ ~ ~

Florida: 1971-1974. I. Introduction and rationale. Florida Marine Research Publications

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~ ~ ~

23: 1-5.

Gallagher, R.M., M.L Hollinger, R.M. Ingle and C.R. Futch. 1972. Marine turtle nesting on Hutchinson Island, Florida in 1971. Florida Department of Natural Resources, Special Scientific Report 37:1-11.

Hendrickson, J.R. and E. Balasingam. 1966. Nesting beach preferences of Malayan sea turtles. Bulletin of the National Museum Singapore 33(10):69-76.

Henwood, T;A. 1987. Movements and seasonal changes in loggerhead turtle, Caretta caret-ta aggregations in the vicinity of Cape Canaveral, Florida (1978-84). Biological Con-servation 40:191-202.

Hillestad, H.O., J.l. Richardson, C. McVea, Jr. and J.M. Watson, Jr. 1982. Worldwide inciden-tal capture of sea turtles. Pages 489-496 in Bjorndal, K.A., ed. Biology and conserva-tion of sea turtles. Smithsonian Institution Press, Washington, D.C.

Hirth, H.F. 1980. Some aspects of the nesting behavior and reproductive biology of sea turtles.

American Zoologist 20:507-523.

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opkins, S.R., T.M. Murphy, Jr., K.B. Stansell and P,M. Wilkinson. 1979. Biotic and abiotic factors affecting nest mortality in the Atlantic loggerhead turtle. Proceedings Annual Conference of Southeastern Fish and Wildlife Agencies 32:213-223.

Hughes, G.R. 1974. The sea turtles of southeast Africa, 1. Status, morphology and distribu-tions. South African Association for Marine Biological Research, Oceanographic Research Institute, Investigational Report No. 35:1-144.

. 1976. Irregular reproductive cycles in the Tongaland loggerhead sea turtle, aretta

~cretta (L) (Cryptodira:Chelonidae). Zoologica Africans t t (2):288-29t.

Martin, R.E., R.G. Ernest, N.W. Walls and J.R, Wilcox. 1989a. Size distribution and seasonal abundance of loggerhead and green turtles in nearshore waters off Hutchinson Island, Florida, Pages 334-335 in Ogren, L, F. Berry, K. Bjorndal, H. Kumpf, R. Mast, G.

Medina, H. Reichart and R. Witham, editors. Proceedings of the Second Western At-lantic Turtle Symposium. Mayaguez, Puerto Rico, 12-16 October 1987. NOAA Techni-cal Memorandum NMFS-SEFC-226.

. 1989b. Long-term trends in sea turtle nesting on Hutchin-son Island, Florida. Pages 111-113 in Eckert, S.A., K.L Eckert and T.H. Richardson, compilers. Proceedings of the Ninth Annual Workshop on Sea Turtle Conservation and Biology. NOAA Technical Memorandum NMFS-SEFC-232.

Mendonca, M.T. and LM. Ehrhart. 1982. Activity, population size and structure of the imma-ture Qhelonia~mdas and Caretta caretta in Mosquito Lagoon, Florida. Cop cia t 982:(1 )

161-167.

Moffler, M.D. and J.F. Van Breedveld. 1979. Nearshore marine ecology at Hutchinson Island, Florida: 1971-1974.X. Benthic algae species list. Florida Marine Research Publications 34: 118-122.

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45

l t

'Hara, J. 1980. Thermal influences on the swimming speed of loggerhead turtle hatchlings.

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~t to low frequency sound. Copeia 1990.

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Owens, D.W. and G.J. Ruiz. 1980. New methods of obtaining blood and cerebrospinal fluid from marine turtles. Herpetologica 36:17-20.

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~

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tion on the nesting of the loggerhead sea turtle (Caretta ~caretta:1971-1984. Copeia 1986(3): 813-816.

Raymond, P.W. 1984. The effects of beach restoration on marine turtles nesting in south Brevard County, Florida. M.S. thesis, University of Central Florida.

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Stancyk, S.E. 1982. Non-human predators of sea turtles and their control. Pages 139-152 in Bjorndal, K.A., ed. Biology and Conservation of Sea Turtles. Smithsonian Institution Press. Washington, D.C.

46

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t

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~

t

albert, O.R., S.E. Stancyk, J.M. Dean and J.M. Will. 1980. Nesting activity of the loggerhead turtle (garetta~caretta in South Carolina. I: A rookery in transition. Copeia1950:(4)709-718.

Taylor, C.B., and H.B. Stewart. 1958. Summer upwelling along the east coast of Florida. Jour-nal of Geophysical Research 64(1):33-40.

Tester, LA. and K.A. Steidinger. 1979. Nearshore marine ecology at Hutchinson Island, Florida: 1971-1974. Vll. Phytoplankton, 1971-1973. Florida Marine Research Publica-tions 34: 16-61.

Walker, LM. 1979. Nearshore marine ecology at Hutchinson Island, Florida: 1971-1974. IX.

Diel plankton, 1973-1974. Florida Marine Research Publications 34: 99-117.

Walker, LM., B.M. Glass and B.S. Roberts. 1979. Nearshore marine ecology at Hutchinson Island, Florida: 1971-1974. Vill Zooplankton, 1971-1973. Florida Marine Research

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Publications 34: 62-98.

Walker, LM. and K.A. Steidinger. 1979. Nearshore marine ecology at Hutchinson Island, Florida: 1971-1974. Vl. Plankton dynamics, 1971-1973. Florida Marine Research Publications 34: 1-1 5.

e Wibbels, T., D. Owens, Y. Morris and M. Amoss. 1984. Sex ratios of immature loggerhead sea

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turtles captured along the Atlantic coast of the United States. Final Report to the Na-

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tional Marine Fisheries Service. Contract No. NA81-GA-C-0039. 47 pp.

~ ~ ~ ~

Williams-Walls, N., J. O'ara, R.M. Gallagher, D.F. Worth, B.D. Peery and J.R. Wilcox. 1983.

~ ~ ~ ~

Spatial and temporal trends of sea turtle nesting on Hutchinson Island, Florida, 1971-

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1979. Bulletin of Marine Science 33(1):5546.

Witherington, B.E. and LM. Ehrhart. 1989. Status and reproductive characteristics of green turtles (Chelonia ~mdas nesting in Florida. Pages 351-352 in Ogren, L., F. Berry, K.

Bjorndal, H. Kumpf, R. Mast, G. Medina, H. Reichart and R. Witham, editors. Proceed-ings of the Second Western Atlantic Turtle Symposium. Mayaguez, Puerto Rico, 12-16 October 1987. NOAA Technical Memorandum NMFS-SEFC-226.

Wtt II.WN.1999.9y 9 I ttl I pt Id t th h 9 lilt NI,~W 1

(Linnaeus, 1766). FAO Fisheries Synopsis, 137:1-78.

Worth, D.F. and M.L Hollinger. 1977. Nearshore marine ecology at Hutchinson Island, Florida:

1971-1974. III. Physical and chemical environment. Florida Marine Research Publica-tions 23: 25-85.

47

orth, D.F., and J.B. Smith. 1976. Marine turtle nesting on Hutchinson Island, Florida, in 1973.

Florida Marine Research Publications 18:1-17.

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150 100 50 1 2 3 4 5 6 7 8 9 NORTH POWER PLANT SOUTH Figure 4. Mean annual number of loggerhead turtle nests in each of the nine 1.25-km-long survey areas, Hutchinson Island, 1971-1988, compared with number of nests during 1989. Horizontal lines are means, boxes enclose plus or minus one standard deviation, vertical lines are ranges, and closed circles are 1989 values (1980 data were excluded because not all areas were surveyed).

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z 300 200 10 A B CDE F G H IJ K L lvIN OPQRST UVWX YZA8 CDE FG H I J ABCDEFGH I J NORTH POWER PLANT SOUTH Figure 6.. Mean annual number of loggerhead turtle emergences in each of the thirty-six 1-km-Iong survey areas, Hutchinson Island, 1981-1988, compared with the number of emergences during 1989. Horizontal lines are means, boxes enclose plus or minus one standard deviation, vertical lines are ranges, and closed circles are 1989 values.

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100 50 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 Figure 8. Number of loggerhead turtle nests in areas 4 and 5, Hutchinson Island, 1971-1989. Arrows denote years during which intake/discharge construction occurred in area 4.

0 5000 4000 0 3000 2000 1000 M 10000 O

z (g 8000

~ 6000 g 4000 l:>> 2000 i

80 60 40 20 1981 1982 1983 1984 1985 1986 1987 1988 1989 Figure 9. Annual number of nests, number of emergences and nesting success along the entire 36.lhkm-long Atlantic coastline of Hutchinson Island, 1981-1989.

30 28 O 26 24 t-22 20 18 120 SO (0

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15 30 5 15 30 5 15 30 5 15 30 5 15 30 5 15 APR MAY JUN JUL AUG SEP Figure 10, Daily loggerhead turtle nesting activity and water temperature, Hutchinson Island, 1989.

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Z 20 20 10 10 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC MONTH OF CAPTURE Figure 14. Mean number of loggerheads captured each month, St. Lucie Plant intake canal, 1977-1988, compared with number of monthly captures during 1989. Horizontal lines are means, boxes enclose plus or minus one standard deviation, vertical lines are ranges, and closed circles are 1989 values.

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100 100 50 50 40 41-45 46-50 51-55 56-60 61-65 66-70 71-75 76-80 81-85 86-90 91-95 96- 101- 106- >110 STRAIGHT LINE CARAPACE LENGTH (cm) 100 105 110 Figure 15. Length distribution (SLCL) of loggerhead sea turtles (N=1,580) removed for the first time from the intake canal, St. Lucie Plant, 1976-1989. No data collected for 72 individuals.

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Figure 16. Weight distribution of live loggerhead sea turtles (¹1,387) removed for the first time from the intake canal, St. Lucie Plant, 1976-1989.

No data available for 265 individuals.

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Figure 17. Length distribution (SLCL) of green turtles (N=276) removed for the first time from the intake canal, St. Lucie Plant, 1976-1989. No data collected for 9 individuals.

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Figure 18. Weight distribution of green turtles (N=271) removed for the first time from the intake canal, St. Lucie Plant, 1976-1989. No data collected for 14 individuals.

b 60 60 MALES FEMALES 50 50 M

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z 20 20 10 10 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC MONTH OF CAPTURE Figure 19. Numbers of adult loggerheads (SLCL > 80.0 cm), including recaptures, removed each month from the intake canal, St.

Lucie Plant, 1976-1989. (N=297)

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1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 Figure 2D. Comparison of captures of adult female loggerheads in the intake canal, St. Lucie Plant, 1976-1989, and numbers of loggerhead emergences in area 4 adjacent to the plant. Nesting activity was not monitored in 1976 and 1978.

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I ~ - --- ---~ Interval between successive captures 20 I

I Interval between first and last capture I

I 250 500 750 1000 1250 1500 1750 2000 RECAPTURE INTERVAL(days)

Figure 21. Cumulative percentage of all loggerhead recaptures occurring within various time intervals between successive captures (N=87) and first and last capture (N=53), St. Lucie Plant intake canal 1976-1989.

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TABLE 1 ESTIMATES OF THE NUMBERS OF LOGGERHEAD TURTLE NESTS ON HUTCHINSON ISLAND BASED ON SURVEYS OF NINE 1.25-KM-LONG SURVEY AREAS, 1971-1989, COMPARED TO THE ACTUAL NUMBER OF NESTS ON THE ISLAND, 1981-1989 Year 1971 1973 1975 1977 1979 1981 1982 1983 1984 1985 1986 1987 1988 1989 Number of nests in the nine 1420 1260 1493 932 1449 1031 1634 1592 1439 1623 1839 1645 1701 1774 1.25-km-long survey areas Extrapolation from the nine 4175 3704 4389 2740 4260 3031 4804 4680 4231 4772 5407 4836 5001 5216 survey areas to the entire island (see text)

Actual number of nests on 3115 4690 4743 4277 4877 5483 4623 4990 5193 the entire island

TA 0 TOTAL NUMBER OF SEA TURTLE CAPTURES AND (NUMBER OF DEAD)

TURTLES REMOVED FROM THE INTAKE CANAL ST. LUCIE PLANT 1976 - 1989 S ecies Year o er ead reen eat erback haw sb> Kem s rsd e Total 1976 33(4) 33(4) 1977 80(5) 5(2) 86(7) 1978 138(19) 6(1) 148(20) 1979 172(13) 3(1) 175(14) 1980 116(5) 10(3) 126(8) 1981 62(5) 32(2) 97(7) 1982 101(16) 110(16) 1983 119(4) 23(4) 142(8) 1984 148(3) 69(2) 220(5) 1985 157(4) 14 172(4) 1986 195(27) 22(i) 220(28) 1987 175(11) 35 6(2) 218(13) 1988 134(6) 42(2) 5(2) 181(10) 1989 111(4) 17(i) 133(5)

Total 1741(126) 286(19) 9(0) 8(0) i>(4) 2061(149)

Annual Meana 131.4 22. 0 0.7 0.6 1.3 156.0 Excludes 1976 (partial year of plant operation).

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TABLE 3 TOTAL NUMBER AND (NUMBER OF DEAD) LOGGERHEAD TURTLES REMOVED EACH MONTH FROM THE INTAKE CANAL ST. LUCIE PLANT 1976 - 1989 Month 1976 1977 1978 1979 1980 1981 1982 1983 January 13 19 24(3) 16 11(1) 6(2) 39 february 8(1) 11(2) 29(1) 21(2) 11(3) 11 13(1)

March 7 27(2) 11 14 6 14 Apr il 5(2) 19(5) 17 0 10 14 0 May 2 1 3(1) 0 7 6 17(4) 4 June 0 5 10 3(1) 8(3) 6 7 7(1)

July 7(1) 4 0 27(2) 0 1 7 August 2 3 12 16(2) 12 6 2(1) 6 September 1 15(1) 1 8(1) 19 2(1) 9(1) 8(2)

October 7 9(1) 17(2) 15(3) 7 0 9(5) 17 November 5(3) 5 15(7) 12 4 0 4(2) 5 December 9 5 4 10 8 3 1(1) 12 Total 33(4) 80(5) 138(19) 172(13) 116(5) 62(5) 101(16) 119(4)

E 3 (continued)

TOTAL NUMBER AND (NUMBER OF DEAD) LOGGERHEAD TURTLES REMOVED EACH MONTH FROM THE INTAKE CANAL ST. LUCIE PLANT 1976 - 1989 Monthly Percent of Month 1984 1985 1986 1987 1988 1989 Total Mean Total Catch January 13 ll 15(2) -

26(3) 7 13 213(11) 16.4 12. 5 February ll 15 16(4) ll 10(3) 6 173(17) 13.3 10.1 March 6 20 14(4) 8(1) 11 4(2) 143(9) 11.0 8.4 April 2(l) 13 20(2) 24(3) 13(2) 11 148(15) 11.4 8.7 May 7 16 12 23(1) 28 13 139(6) 9.9 8.0 June 28(1) 17 20(1) 26(1) 30 16 183(8) 13.1 10.7 July 12(1) 20(3) 26(2) 19(1) 5 21(1) 156(11) 11.1 8.7 August 26 19(1) 34(6) 17(1) 3 15 173(11) 12.4 10. 0 September 16 14 9(4) 11(1) 2 119(11) 8.5 6.9 October 10 7 11(2) 2 3 117(13) 8.4 6.4 November 9 3 5 5(1) 85(13) 6.1 4.7 December 8 2 10 9 2 92(1) 6.6 4.9 Total 148(3) 157(4) 195(27) 175(11) 134(6) 111(4) 1741(126)

Excludes 1976 (partial year of plant operation).

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TABLE 4 TOTAL NUMBER AND (NUMBER OF DEAD) GREEN TURTLES REMOVED EACH MONTH FROM THE INTAKE CANAL ST. LUCIE PLANT 1976 - 1989 Month 1976 1977 1978 1979 1980 1981 1982 1983 January 2 1 0 0 20(1) 8(1)

February 2(1) 2 1 5(1) 7 March 0 2 0 4(1) 1 3(2)

April 1(1) 0 1(1) 0 1 May l(l) 0 0 June 1 1(1)

July 0 0 August 2(1)

September October November 4(1)

December Total 5(2) 6(1) 3(1) 10(3) 32(2) 23(4)

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TAB 4 (continued)

TOTAL NUMBER AND (NUMBER OF DEAD) GREEN TURTLES REMOVED EACH MONTH FROM THE INTAKE CANAL ST. LUCIE PLANT 1976 - 1989 Monthly Percent of Month 1984 1985 1986 1987 1988 1989 Total Mean Total Catch January 37(1) 4 1 4 12 3(1) 93(4) 7.2 32.5 February 10 1 1 11 45(2) 3.5 15. 7 March 6(1) 30(4) 2.3 10.5 April 3 3 18(2) 1.4 6.3 May 8(i) 0.6 2.8 June 6(2) i7(3) 1.2 5.9 July 0.6 2.8 August 9(i) 0.6 3.1 September 0.4 1.7 October 12 0.9 4.2 November 4(l) 1 18(2) 1.3 6.3 December 23 1.6 8.0 Total 69(2) 14 22(1) 35 42(2) 17(1) 286(19)

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TA 5 NUMBER OF MONTHLY CAPTURES BY SIZE CLASS FOR LOGGERHEAD TURTLES REMOVED FROM THE INTAKE CANAL ST. LUCIE PLANT 1977 - 1989a Size classes (SLCL in cm b Juveniles/Sub-Adults Transition Adults Month 41-50 51-60 61-70 Total Percenta e 71-80 Percenta e 81-90 91-100 >100 Total Percenta e January 16 83 73 172 14.8 23 12.2 10 2 0 12 4.1 February 72 54 137 11.8 17 9.0 1 0 2.4 March 57 48 113 9.7 16 8.5 6 0 2.7 April 12 44 49 105 9.0 19 10.1 4 0 12 4.1 cn May 10 48 32 90 7.7 11 5.8 16 17 0 33 11.3 June 9 46 43 98 8.4 13 6.9 20 3 64 21.9 July 4 43 34 81 7.0 12 6.4 27 25 3 55 18.8 August 42 48 96 8.3 20 10.6 33 17 1 51 17.4 September 45 37 85 7.3 12 6.4 9 2 18 6.1 October 7 35 30 72 6.2 18 9.6 14 1 1 16 5.5 November 20 24 48 4.1 18 9.6 4 1 10 3.4 December 5 33 26 64 5.5 9 4.8 4 0 2.4 Total 95 568 498 1161 188 172 110 11 293 X of Total 70.7 11.4 17.8 aExcludes 1976 (partial year of data) bNo data were collected for 66 individuals.

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SR TA 6 RELATIVE CONDITION OF SEA TURTLES REMOVED FROM THE INTAKE CANAL ST. LUCIE PLANT 1976 - 1989 Relative Lo erheads Greens Leatherbacks Kem 's ridle s Hawksbills All s ecies condition Number Number Number Number Number Number 344 19.8 99 34.6 1 11.1 2 11.8 6 75 0 452 21 9

< 436 25.0 49 17.1 1 ll 1 3 17 6 2 25.0 491 23.8 479 27.5 .

78 27.3 6 66.7 3 17.6 566 27.5 265 15.2 29 10.1 1 11.1 3 17.6 298 14.5 81 4.7 7 2.4 2 11.8 90 4.4 126 7.2 19 6.6 4 23.5 149 7-2 10 0.6 5 1.7 15 0.7 TOTAL 1741 286 17 2061.

1 Excellent - normal or above normal weight, active, very few or no barnacles or leeches, no wounds.

2 Very good - intermediate good to excellent.

3 Good - normal weight, active, light to medium coverage of barnacles and/or leeches, wounds absent, healed or do not appear to debilitate the animal.

4 Fair - intermediate'oor to good.

5 Poor - emaciated, slow or inactive, heavy barnacle coverage and/or leech infestation, debilitating wounds or missing appendages.

6 Dead 7 Alive but otherwise condition not recorded.

I FLORIDA POWER 8c LIGHT COMPANY ST. LUCIE UN% NO. 2 ANNUALENVIRONMENTALOPERATING REPORT (FPL49)

VOLUME II

ANNUAL ENVIRONMENTALOPERATING REPORT Introduction The St. Lucie Unit 2 Environmental Protection Plan (EPP) requires the submittal of an annual report for various activities at the plant site including the reporting on sea turtle monitoring programs, and other matters related to Federal and State environmental permits and certifications. This report and Volume II described below fulfill these reporting requirements.

II. Sea Turtle Monitorin and Associated Activities A report on aquatic and terrestrial sea turtle monitoring programs to satisfy Sections 4.2.1 (Beach Nesting Surveys), 4.2.3 (Studies to Evaluate and/or Mitigate Intake Canal Mortality) and 4.2.5 (Capture and Release Program) is concurrently submitted in a separate report (AB-603, Vol. II) prepared by Applied Biology, Inc. of Jensen Beach, Florida and Atlanta, Georgia.

Studies to evaluate and/or mitigate intake entrapment required by Section 4.2.2 of the EPP have been previously performed. A final report was submitted to the Office of Nuclear Reactor Regulation on April 18, 1985. With submittal of that report, the EPP requirement was fulIiiled and will not be readdressed in this or future reports.

Surveillance and maintenance of the light screen to minimize sea turtle disorientation as required by Section 4.2.4 of the EPP is ongoing. The Australian Pine light screen, located on the beach dune between the power plant and the ocean, is routinely surveyed to

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determine its overall vitality. The tree line is surveyed for any gaps occurring from tree mortality, which would result in unacceptable light levels on the beach. Trees are replaced as necessary to maintain the overall integrity of the light screen.

III. Other Routine Re orts The following items for which reporting is required are listed by section number from the plant's Environmental Protection Plan (EPP):

5.4.1.(a) EPP NONCOMPLIANCES AND CORRECTIVE ACTIONS TAKEN No noncompliances under EPP Section 5.4.1(a) were determined to have occurred during 1989.

5.4.1.(b) STATION DESIGN AND OPERATION CHANGES TESTS AND EXPERIMENTS AFFECTING THE ENVIRONMENT No plant site activities were determined to be reportable under Section 5.4.1(b) during 1989.

5.4.1.(c) NONROUTINE REPORTS SUBMIITED TO THE NRC FOR THE YEAR 1 8 IN ACCORDANCE WITH EPP SUBSECTION 5..2:

1. Submittal of an NPDES Permit modification request to EPA; sumitted to the NRC on April 13, 1989.

2. Report concerning an exceedance of the NPDES Permit limitation for pH from the Unit 1 Sewage Treatment Plant effluent; reported to the NRC on May 11, 1989.

3. Report concerning an exceedance of the NPDES Permit limitation for free available oxidants in the once through cooling water discharge; reported to the NRC on June 7, 1989.

4. Report concerning an exceedance of the NPDES Permit limitation for iron from the radwaste system effluent; reported to the NRC on July 17, 1989.

5. Report concerning an exceedance of the NPDES Permit limitation for maximum once through cooling water discharge temperature (discharge canal terminus);

reported to the NRC on October 16, 1989.

The following reports were submitted to the NRC for the year 1989 for informational purposes although not required under provisions of EPP subsection 5.4.2:

1. Sea turtle activities report dated April 24, 1989 for the first quarter 1989.

2. Sea turtle activities report dated August 2, 1989 for the second quarter 1989.

3. Sea turtle activities report dated November 2, 1989 for the third quarter 1989.

4. Sea turtle activities report dated January 23, 1990 for the fourth quarter 1989.